Ever seen this bumper sticker? “It will be a great day when our schools get all the money they need and the Air Force has to hold a bake sale to buy a bomber.”

Unfortunately for the writer of this little zinger, it’s also wrong.

In fact, irony abounds in this case. Education spending has been rising for quite a while now. Per-pupil federal expenditures on education (in constant dollars) have nearly tripled over the last half-century. The Air Force, meanwhile, isn’t holding bake sales, but at the rate things are going, it might have to start.

All four branches of our military are grappling with budgets cuts -- cuts that add up to fewer troops, aging equipment, and degraded levels of readiness.

Four of America’s top military officers testified on Sept. 15 before the Senate Armed Services Committee on the long-term budget challenges they’re facing. And what they had to say should concern anyone who cares about America’s ability to protect itself.

What happens when a typical household sees its income cut? It falls back on savings. That meets the present need, but what about next time? Its ability to deal with problems down the road has been compromised.

Well, the same goes for our armed services. So much chronic underfunding has jeopardized its ability to deal with future threats. They shift funds to cover this year’s missions. But what about next year’s, and the year after that?

Gen. David Goldfein, Air Force chief of staff: “Pilots who don’t fly, maintainers who don’t maintain, controllers who don’t control, will walk … if we don’t give them the resources. … Where we have low readiness, we have our lowest morale.”

You can’t attract and keep talented people in your ranks if you don’t give them the tools necessary to do the job properly. That’s true in any profession, the military included. Our hard-working troops do the best they can with what they’ve got, but if we don’t give them the best equipment and training possible, can we be surprised if they’re tempted to go elsewhere?

Gen. Robert Neller, Marine Corps commandant: “We’re making it now on the backs of those sergeants and staff sergeants out there that have to do work twice.”

Making it, perhaps, but for how long? Besides, it’s hardly fair to put such a strain on enlisted leaders, who are forced to do more with less.

Gen. Milley: “What we want is to deter … and the only thing more expensive than deterrence is actually fighting a war, and the only thing more expensive than fighting a war is fighting one and losing one. … It’s an investment that’s worth every nickel.”

Making unwise defense cuts is more than just demoralizing and damaging to readiness (though that’s certainly bad enough). It is, as the saying goes, penny-wise and pound-foolish. Building and maintaining a world-class military isn’t smart only when you use it for combat. Simply having such a military can help you avoid a fight in the first place.

So what is Congress doing to help?

“Every year, Congress writes two major defense bills: the defense appropriations bill, which funds the military, and the defense authorization bill, which establishes policies and the legal authority for what the military can do,” writes defense expert Justin T. Johnson.

Two critical pieces of legislation. Yet again and again, lawmakers get caught up in partisan squabbles that delay these crucial funds. In fact, the last time Congress passed a defense funding bill before the new fiscal year began was Sept. 27, 2008. It hasn’t happened once since President Obama took office.

Playing politics with our security? Allowing needless delays that put readiness at risk? This has to stop.

History shows the folly of trying to buy defense on the cheap. Let’s turn this around -- before we wind up making a very deadly and costly mistake.